[compiler] Remove old hack for arguments adaptor frames

.. which applied to the AssemblePopArgumentsAdaptorFrame
function that no longer exists.

Drive-by: Remove unused functions in mips, mips64.

Bug: v8:11306
Change-Id: Ia47c4287a452afe0aea2be0902cb3adce15f02bf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2649029Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72313}

src/compiler/backend/instruction-selector.cc

@@ -951,18 +951,12 @@ void InstructionSelector::InitializeCallBuffer(Node* call, CallBuffer* buffer,
   bool call_use_fixed_target_reg = (flags & kCallFixedTargetRegister) != 0;
   switch (buffer->descriptor->kind()) {
     case CallDescriptor::kCallCodeObject:
-      // TODO(jgruber, v8:7449): The below is a hack to support tail-calls from
-      // JS-linkage callers with a register code target. The problem is that the
-      // code target register may be clobbered before the final jmp by
-      // AssemblePopArgumentsAdaptorFrame. As a more permanent fix we could
-      // entirely remove support for tail-calls from JS-linkage callers.
       buffer->instruction_args.push_back(
           (call_code_immediate && callee->opcode() == IrOpcode::kHeapConstant)
               ? g.UseImmediate(callee)
               : call_use_fixed_target_reg
                     ? g.UseFixed(callee, kJavaScriptCallCodeStartRegister)
-                    : is_tail_call ? g.UseUniqueRegister(callee)
-                                   : g.UseRegister(callee));
+                    : g.UseRegister(callee));
       break;
     case CallDescriptor::kCallAddress:
       buffer->instruction_args.push_back(

src/compiler/backend/mips/instruction-scheduler-mips.cc

@@ -1267,11 +1267,6 @@ int PrepareForTailCallLatency() {
          Latency::BRANCH + 2 * SubuLatency(false) + 2 + Latency::BRANCH + 1;
 }
 
-int AssemblePopArgumentsAdaptorFrameLatency() {
-  return 1 + Latency::BRANCH + 1 + SmiUntagLatency() +
-         PrepareForTailCallLatency();
-}
-
 int JumpLatency() {
   // Estimated max.
   return 1 + AdduLatency(false) + Latency::BRANCH + 2;

src/compiler/backend/mips64/instruction-scheduler-mips64.cc

@@ -794,11 +794,6 @@ int PrepareForTailCallLatency() {
          Latency::BRANCH + 2 * DsubuLatency(false) + 2 + Latency::BRANCH + 1;
 }
 
-int AssemblePopArgumentsAdoptFrameLatency() {
-  return 1 + Latency::BRANCH + 1 + SmiUntagLatency() +
-         PrepareForTailCallLatency();
-}
-
 int AssertLatency() { return 1; }
 
 int PrepareCallCFunctionLatency() {